Hybrid analysis (MM-UTD) of EM scattering from finned convex objects

It is a formidable task to analyze the electromagnetic (EM) scattering from complex structures containing both electrically large and small parts because, in general, neither low nor high frequency techniques alone can provide a tractable solution to this problem. The method of moments (MM) is a very accurate mathematical technique which is commonly used to solve the governing integral equation but usually involves the computation, storage, and inversion of an extremely large matrix when analyzing electrically large objects. The uniform geometrical theory of diffraction (UTD) is an asymptotic high frequency ray method which describes through closed-form, physically insightful expressions, the basic radiation mechanisms such as reflection from a surface or creeping waves, provided the pertinent UTD solutions are available. However, there are a limited number of ray mechanisms for which UTD field expressions currently exist. A systematic combination of these two techniques can be employed to analyze complex objects in a far more manageable and efficient manner than is possible by either method alone. A hybrid combination of the MM and the UTD has been developed for treating an electrically large, perfectly conducting (PEC) convex scatterer, containing appendages which can be modeled by a set of PEC plates. The development of such a hybrid technique is useful, for example, in the prediction of the radiation/scattering from complex aerospace vehicles.